guideline levels at a few sites. Arsenic was above ER‐M at one site only, whilst nickel was the one with a few sites exceeding the ER‐M value.
168. Also for metals, concentrations recorded during the present study are comparable with the surrounding environment, with some values actually showing a better state. For example, records in the CSEMP database (CSEMP, 2012) show that levels of Cadmium and Mercury in the Anglian region are below above CSEMP ER–L levels, but that for Lead and Zinc, the values are above ER‐L levels The CSEMP database (CSEMP, 2012), although limited within the Anglian region, provides records showing that high concentrations of nickel and arsenic have been recorded in the area.
4.3.3 PCBs 169. For the Anglian region the MERMAN database does not hold records of individual concentrations the ICES7 PCB congeners in offshore sediment (CSEMP, 2012b); only one record is available for an inshore site where the levels of the individual PCBs are all below the Environmental Assessment Criteria (EAC). Due to the paucity of the historical data, it is however difficult to assess the findings of this report against typical environmental conditions. Values of the sum of ICES7 close to background are rare and sites where these concentrations are below the EAC are mainly confined to areas away from industrial activity and most offshore locations in the North Sea. It is therefore likely that the findings of this report reflect the typical environmental condition of the area.
4.3.4 Organotins (Tributyl‐tin) 170. All tributyl‐tin (TBT) concentrations found at sites sampled in this study fall in Class C (where concentrations range from 2μg / kg to < 50μg / kg) with a concentration very close to the lower end of the range (all <4µg/kg); these are not expected to “affect the reproductive capability of sensitive gastropod species” (OSPAR, 2009). Therefore, it is unlikely that levels recorded by the present study will present a problem in this respect.
Benthic Characterisation Report November 2013
East Anglia THREE and FOUR Offshore Cable Corridor
